The present invention relates generally to the deployment of liners within wellbores, and particularly to the deployment of flush bore liners.
In a variety of applications, wellbores are lined with a liner, e.g. a liner pipe. Exemplary applications comprise oil and gas wells accessed by wellbores drilled into subterranean formations.
In some of these applications, particularly when the wellbore is a lateral wellbore, frictional drag is created between the bore hole and the liner creating difficulty in moving the liner into proximity with the bottom of the wellbore. The friction acts against the outside surface of the liner and tends to buckle or xe2x80x9ccorkscrewxe2x80x9d the liner. The buckled or corkscrewed liner often forms a long, helical shape in the wellbore that forces the liner against the wellbore walls to create even greater frictional forces. This problem is particularly pronounced with conventional systems where force is applied to the liner at the very top to push the liner into the hole while the frictional resistance begins from the bottom of the liner.
Attempts have been made to reduce these frictional forces by pulling the liner from a lower or bottom region rather than pushing from the top. However, tools used to pull the liner are designed to engage features that extend inwardly from the liner, such as a setting sleeve having internal steel threads protruding into the bore of the liner to engage the running tool. However, once the liner is deployed and cemented in place, the inwardly extending features remain and cannot be drilled with a conventional rock bit. Accordingly, if the full inside diameter of the liner is needed or desired, the inwardly extending features, e.g. threads, must be removed by special milling tools. This, of course, incurs additional costs to the well operator due to the extra tools required and the lost production time during milling of the threads.
The present invention relates generally to a technique for lining a wellbore, such as a lateral wellbore. The technique allows the use of a flush bore liner that may be deployed in a wellbore by pulling the liner from a lower region. The technique utilizes a running tool that may be selectively coupled to the liner without utilizing features that cannot be removed from the liner with a conventional rock bit.